NINE years ago, Marissa Pomarico was roused from her Sunday morning dose of the Three Stooges by a shotgun blast that ripped through her mother’s chest.

Within minutes, four members of her family lay dead in their Staten Island home, slain by the little girl’s stepfather.

The murders made front-page headlines, but for 10-year-old Marissa, it triggered a tragic odyssey that ended last week with the girl now known as America’s most-wanted porn star being tossed in a cell on Rikers Island.

Marissa’s half-sister, Kim Alvarado, was also jailed.

The pair are charged with snatching Kim’s two kids from a foster home in May and fleeing cross-country. But some say Kim, 31, used 19-year-old Marissa – who spent months having sex on film in order to support Kim and her family.

Marissa never had a chance.

In the decade between her family’s massacre and her sex-film debut and arrest, Marissa shuttled from an aunt’s house to her elderly father’s, to several upstate fosters homes. All the while, she lived with horrific memories and clung to, some say, a troubled and manipulative big sister.

By the time the girls moved from Sheepshead Bay to the home at 9 Evan Place in the Arden Heights section of Staten Island, their mother, Angela Alvarado, had been married twice.

Angela’s then-husband, Patrick Pomarico, was a contractor in his 60s. When the couple split up a few years later, Angela married Philip Guerriero, a local construction worker.

“It was a normal house ’til Philly moved in,” said Nina Burnett, a close family friend who still lives up the block. “He fought all the time with Angela and the kids, swearing and screaming.” Burnett also frowned upon another family member.

“I never trusted Kim. She had lots of boyfriends. She was picked up for shoplifting. A real bad influence on Marissa,” Burnett told The Post.

STILL, Marissa seemed well adjusted, attend ing PS 36 with kids from the block. “She was clean, polite, never misbehaved,” said another neighbor. That promise for a decent, happy life disappeared in a flash on Feb. 20, 1995.

Angela and her 26-year-old son, Raymond, were supposed to go to Home Depot the day before to pick up a new toilet for the family’s ground-floor apartment, which Philip – then unemployed – was renovating.

Instead, they spent the day – and night – gambling in Atlantic City, said Gregg Koleniak, a now-retired Staten Island detective who investigated the case.

When Philip got home the next day, he was steaming, while Angela cooked a big family meal. Kim, then 21 and living in Brooklyn, was scheduled to come over later.

Little Marissa was in the den in her pajamas, watching Larry, Curly and Moe on the big-screen TV. After her mom chastised her stepdad for eating out of a pot of sauce on the stove, he went to the basement and loaded his sawed-off shotgun.

Then he came back upstairs shortly before noon and shot Angela in cold blood.

Screams raced through the house as Philip proceeded to mow down Marissa’s grandfather, half-brother and grandmother.

Philip then put the gun to Marissa’s head and said, “I’m going to let you go.”

She ran upstairs to her room, knelt down and started praying.

All was quiet until he came into her room, gun still in hand.

“I won’t tell anyone,” the little girl pleaded.

Her stepdad then put his finger to his lips, as if to say “shhhh,” walked back downstairs and drove off in his Lincoln Town Car.

Later that day, Philip turned himself into the 123rd Precinct station house and confessed. He’s now serving 18 years to life in prison.

Burnett told The Post she offered to adopt Marissa, but child-welfare authorities didn’t want the girl living on the street where the bloody rampage took place.

They also did not want her living with Kimberly, she said.

Instead, she stayed at an aunt’s house on Staten Island for the short time, then moved in with her father in upstate New York. But he was nearing 70, so he could not care for her for long. That’s when Marissa was bounced around to several foster homes in upstate Ulster County, all the while suffering flashbacks to the carnage that took her mom’s life.

Though she was in therapy to treat the trauma, one shrink’s prescription seemed grossly ill-advised, experts say.

On Veterans Day 2000, Marissa was brought back to 9 Evan Place by an uncle, psychiatrist and agent from the bank that had foreclosed on the family home.

BY that time, neighbor hood kids had taken to calling it “the dead house,” and with good reason. It had been boarded up for five years, preserving the crime scene like a museum exhibit.

The psychiatrist knocked on the door of the adjoining house and asked if the then-14-year- old girl could peer into her old back yard.

“I took her out back, where she stared across the way for a few moments before running off crying,” said Linda Venturino, who moved her family five months after the crime.

The bank agent then asked Venturino’s husband to help him remove the chains from the front door of the house.

“I went in first to make sure there were no rats running around,” Mike Venturino told The Post. But what he saw shocked him more than rodents.

“There was blood splattered on the wall behind the couch,” where Marissa’s grandpa had been shot, he said. “There was also a blanket on the living-room floor with bloodstains around it and a crucifix on top,” where her mom had been shot.

And the pot of sauce that sparked the horrors was still on the stove.

Shortly thereafter, the shrink took Marissa into the house, where the two stayed for about an hour.

“Going in there to relive what happened must have been more harmful than helpful to her,” Mike Venturino said.

Manhattan psychiatrist Vivian Pender agrees.

“Common sense says this isn’t the sort of thing you do. I don’t know anyone who would,” said Pender, who works with adolescents but was not involved in Marissa’s case.

From the age of 14 to 18, Marissa lived in upstate Rosendale with foster parents Donald and Marcell Hasenflue. Like 9 Evan Place, the contractor’s house had an above-ground pool, where Marissa could swim with her foster brother and sister.

By many accounts, her years in the sleepy town were relatively normal.

Marissa spent three years at Rondout Valley HS, the local public school, before transferring to John A. Coleman, a private Catholic school.

“She was a nice, quiet, calm girl who dated a few guys from Rondout,” said Rosendale Police Officer Rob Fischer.

And she had no criminal record “other than a few parking violations,” a local judge told The Post.

Hasenflue, however, noted a marked difference in Kim, who occasionally visited his home.

“Marissa’s sister looked to me like someone who has a drug problem,” he said.

Kim, meanwhile, had given birth to son Justin Scaglione, now 5, and daughter Lexie Fenell, now 1.

To help make ends meet, the single mom “worked off and on at a friend’s auto shop on Staten Island,” said her attorney, Jason Leventhal.

“She loved her kids and only wanted what was best for them,” he said.

But the city Administration for Child Services saw things differently.

AFTER Lexie was acci dentally burned by an iron in Kim’s apartment eight months ago, they began an investigation. Both kids were soon placed in foster care with distant cousin Jack Lichaa and his wife on Lott Lane in Staten Island.

“Kim was here 18 hours a day trying to control everything,” Lichaa said. “She drove my family insane and had no idea how to control Jason.”

Marissa would also visit, though only every other week or so, he said.

Though Lichaa loved the kids – going so far as to spend more than a thousand dollars on new bedding for them – Kim’s intrusions grew too much for him after three months.

On Saturday, May 15, he arranged to return the kids to ACS.

“That’s when Kim panicked,” he told The Post.

The next day, while Lichaa was out fishing, Kim and Marissa sped off with the kids in a silver Volkswagen Jetta, according to investigators.

After ditching the car in Brooklyn, they hopped the subway to JFK and flew to L.A. on JetBlue.

A few months earlier, Marissa had again returned to Evan Place with Kim and the kids. This time she told Burnett she was living on her own while working part-time and going to college.

“I loved her like a daughter, so I was happy to see her doing well. But Kim still seemed like trouble,” she said.

L.A. proved too expensive for the pair, so they made their way eastward – but not before getting Marissa an alias.

While holed up at a boarding house, the women acquired a photo ID of one Jessia Zender, a student at the University of Nevada, Las Vegas, sources said.

That would prove key in keeping the pair afloat in the ensuing months.

Two weeks later, they took a two-bedroom flat in the Pinnacle apartment complex on the outskirts of Las Vegas.

It was there that the bikini-clad teenager made her first porn-industry contact, sources say.

She was approached by an unidentified couple who asked her if she’d be interested in modeling. Sorely in need of money, Marissa said yes.

WITHIN the next few weeks, she was making up to $1,000 a day for appearing in XXX videos like “Teen Dreams 9” and “Peter North’s North Pole 52.”

Fans knew her as “Brittany” and “Jewel Affair,” while agents and producers knew her as Jessia Zender.

One Las Vegas agency listed her as 23 years old and “available for toys, solo, BG [boy-girl] and GG [girl-girl].”

She worked mostly in L.A., but also flew to shoots in Florida and Massachusetts.

Kim, meanwhile, pushed her to film as much smut as possible, one photographer, speaking confidentially, told The Post.

“She called me nonstop looking for work for her sister,” he said. “Kim’s a real wack job, probably schizoid or bipolar.

“Marissa made a bad mistake listening to her, which is a shame because Marissa is real cool and dependable. If she had been on the up and up, she could have risen to the top.”

One Boston producer, who also spoke confidentially, was less enthusiastic.

He said he had to shut down a shoot after Marissa failed to produce ID proving that she was at least 18 years old.

“I lost thousands of dollars,” he said.

Four months ago, NYPD detectives got a tip from someone who’d seen Marissa on an Internet porn site. That led to a Nov. 20 segment on “America’s Most Wanted,” which in turn prompted tips from people in Las Vegas who recognized Kim as the woman taking Jason and Lexie trick-or-treating.

TIPS also poured in from people in the porn industry – not so much concerned with the kids as with the fact that hiring underage talent is bad business.

When Marissa’s agent, Tara Miali, learned of the warrant out for her client’s arrest, she convinced Marissa to surrender to the FBI in L.A. on Nov. 21.

Kim was picked up by the feds at a Motel 6 in San Bernardino, Calif., the same day. Jason and Lexie were unharmed.

Kim and Marissa were arraigned on Staten Island last week. Both were indicted on two felony counts of custodial interference in the first degree and two misdemeanor counts of endangering the welfare of a child. If convicted, each could spend up to four years behind bars. Their next court date is Wednesday.

Both Lexie’s and Jason’s fathers have since filed for custody of their kids, The Post has learned. Moments after the judge set her bail at $250,000, Marissa broke into tears outside the courtroom.

“She called me from Rikers and said she’s doing OK,” said Hasenflue. “She’s a messed up kid, but I’m really glad they found her and she turned herself in.”